The present invention relates to a method and device for regulating the pressure in a hydraulic system for operating at least one actuator in a subsea installation.
In developing petroleum fields, a need might exist for hydraulic fluid pressures other than those provided by the ordinary high pressure (HP) and low pressure (LP) lines running to the subsea installation. One might find an example of such a need in connection with an “intelligent well”, where the use of sliding sleeve valves enables the control of production from more than one zone. Generally, the pressure needed for the actuation of such valves is lower than what is necessary for the SCSSV (Surface controlled Subsurface safety valve).
One possible solution for this situation is to run more than two hydraulic fluid lines down to the subsea installation through the umbilical. However, the use of such a solution is not favored when large distances exist between the source of hydraulic fluid and the subsea installation, due to increased installation and operation costs.
Another possible solution is to provide a system for regulating the pressure at the subsea installation. Normally, this involves using one system to regulate the pressure needed for operation of one specific valve and another system to regulate the pressure needed for operation of another specific valve. However, this again is a costly and volume demanding solution.